Sometimes it becomes desirable to pump kill fluids from the annulus between the casing and well tubing of an oil and/or gas well and into the tubing for killing the well. One type of valve used is a retrievable valve set in the sidepocket of a mandrel in which a piston is pumped downwardly out of the bottom of the sidepocket to provide communication between the annulus and the tubing. However, the sidepocket of a mandrel is frequently positioned at a weld which causes buildup at the lower end of the mandrel pocket. While such a welding buildup does not affect the passage of fluids, the buildup may block the physical movement of a downwardly moving piston thereby preventing the piston from moving out of the lower end of the sidepocket and establishing communication between the sidepocket and the tubing bore.
The present invention is directed to a dump and kill valve for use in a sidepocket of a mandrel which moves upwardly in the smooth polished bore of the sidepocket for ease of movement for opening the sidepocket to a full flow of kill fluid.